<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta http-equiv="X-UA-Compatible" content="IE=edge">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Document</title>
</head>
<body>
    <script>
        let kvArray = [{key: 1, value: 10},
               {key: 2, value: 20},
               {key: 3, value: 30}];
        let newArray = kvArray.map(kv => {
            console.log(this);
            console.log(date);
            let obj = {};
            obj[kv.key] = kv.value * 10;
            return obj;
        },date = new Date())
        // obj = (kv => (kv.value * 10));
        console.log(newArray);


    </script>
</body>
</html>